The present invention pertains to submersible pressure vessels, such as bathyscaphes, which may be used for deep-sea exploration. More particularly, the invention relates to a monitoring camera for such a pressure vessel.
The submersible pressure vessels adapted to operate under water and above water must be provided with means for controlling safety in the water environment. These controlling means usually comprise a television camera which supplies signals to a monitor installed within a monitoring station outside the pressure vessel.
It is known that monitoring cameras are mounted in the pressure vessels. Such installation is disadvantageous because a camera or a number of cameras being used usually restrict the volume in the pressure vessel. The pressure vessels of the foregoing type which operate in a deep-sea area are subjected to the occurence of oxygen-helium-air mixture within the pressure vessel, which mixture influences the amount of nitrogen in air in the vessel. This takes place particularly at a great depth under water.
When the pressure vessel is not reliably sealed against penetration of helium, the latter may be pressed inside the camera housing. During the decompression of the pressure vessel when the vessel emerges from a great depth, helium can not escape from the camera quickly. This leads to a pressure differential between the interior of the monitoring camera and the exterior thereof, which pressure differential may cause the explosure in the camera.
The known installations of monitoring cameras are used only when the camera is reliably sealed against helium. However, the cost of such sealing is considerably high.
In order to avoid the shortcomings encountered in the known installations, pressure vessels have been provided with port-holes extended from outside into the interior of the pressure vessel. This conventional installation permitted one to overcome the disadvantages relating to a space restriction within the vessel and to occurence of helium-air mixture in the vessel. However, this otherwise satisfactory installation was found disadvantageous. It has been recognized that a beam path of the camera installed outside the pressure vessel is limited by the port-hole because the walls of this port-hole act as a screen.
Furthermore, such installation is affected by a medium between the camera-objective-lenses and a glass of the port-hole. When the pressure vessel is located at the bottom of a sea the eye-piece of the optical system in the vessel may be eventually deteriorated by fine particles which occur at the bottom of a sea.
When the vessel operates above a water level air may be found between the camera and the port-hole. This fact leads to distortion of observation in the device since the port-hole does not have a sufficient light which happens frequently. In this case a picture to be viewed is reflected which causes the distortion of the optical image to be observed.
A further disadvantage of the outside installations of cameras is that changing of a camera is a time-consuming process because each new camera must be adjusted to a desirable portion of the pressure vessel.
These and other objects of the invention are attained by a monitoring camera for a submersible pressure vessel, particularly a bathyscaphe, which includes an interior and a wall surrounding the interior and having an inner side, the camera comprising a rear portion outside said pressure vessel and a front portion installed in an opening of said wall; and at least one lens located at the interior of said pressure vessel and sealingly covering said front portion, said lens projecting only slightly into said interior from said wall.
By the above-described assembling of the monitoring camera in the pressure vessel the aforementioned disadvantages of the conventional installations may be easily avoided.
The monitoring camera of the invention assures practically complete inspection in the pressure vessel because a dead angle of observation occured in the known devices is completely avoided.
By mounting of the monitoring camera in an opening of the wall of the vessel the adjustment of the monitoring camera is facilitated. When the camera is changed the new camera is easily adjusted.
According to the invention, the rear portion may be realisably-detachably connected to said front portion.
The front portion may include a cylindrical element extending through said opening.
The camera may include an optical system having two parts, said first part including said one lens and being accommodated in said front portion, said second part being accommodated in said rear portion of the camera.
The first portion of the optical system may be a front optic, said rear portion accommodating the remaining part of the camera. Said front optic may be a wide-angle optic. A wide-angle optic or lens is a closing part of the optical system which part is mounted in the front portion of the camera. By utilizing the wide-angle optic installed in the above-described fashion the camera does not restrict the volume inside the pressure vessel.
It is particularly advantageous that the rear portion of the camera is releasably-detachable connected to the front portion of the camera.
The rear portion of the camera may be connected to said front portion by a bayonett joint.
The mounting of the remaining part of the camera in the rear portion of the camera leads to the fact that easy changing of cameras is possible when desired.
The releasable connection of two portions of the camera is particularly advantageous under conditions when the pressure vessel operates above water for a long time, but the camera is under water. Under conditions of the operation above water a standard camera may be used as a front optic, which camera must be reliably protected against water splashes whereas for under water installations the front optic is connected to the camera positioned under water.
One or more lenses may be utilized in the camera. To overcome a pressure differential within the pressure vessel caused by destructions within the vessel two lenses are spaced from one another and sealed within the front portion of the camera.
The front portion may include at least one seal mounted in said cylindrical element to seal said one and second lenses and said space against a gas which may be penetrated into said space. Helium which may be collected in this space from oxygen-helium-ambient must be removed from this space in order to prevent the explosure which may occur during compression of the pressure vessel under water.
A capillary channel may be formed in the cylindrical element of the front portion, said channel extending from said space to outside the pressure vessel.
This channel may have an end which is open toward said rear portion.
Helium collected in said space may escape through the capillary channel without causing a substantial pressure drop in case the outer lense is accidentally destroyed.
The camera may further include an over pressure-operative valve mounted at said end.
The camera may also include a suction device connected to said channel.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.